Spring fastener



March 10, 1942.

G. A. TINNERMAN SPRING FASTENER Original Filed Oct. 1, 1936 2Sheets-Sheeil III/Ill!) nflmw m m W51 1 N A Q a} .Z m v 6/6 W E g Re.22,049 v 2 Sheets-Sheet 2 INVENTOR. 650x55 14 77NNRMHN gait, 7 7;ATJTORNEYS G. A. TINNERMAN SPRING FASTENER Original Filed Oct. 1, 1936March 10, 1942.

neiuueafmsr. 10, 1942 srmc FASTENER .George A. Tinnerman, Cleveland,Ohio, assignor, by mesne assignments, to Tinnerman Products, Inc.,Cleveland, Ohio, a corporation of Ohio Original No. 2,239,797, datedApril 29, 1941, Serial No. 103,516, October 1, 1936. Application forreissue September 17, 1941, Serial No. 411,263

, '14 Claims.' (01. 85-36) This invention relates to spring fasteners,and

. particularly those which are'adapted to be used in conjunction with abolt for holding two .or more articles together.

Spring fasteners of this type have becn deaf signed to engage onlyonehelix. of a'bolt thread for the purpose of effecting an assembly. Ihave.

found, however, that a single thread-engaging by bendinga part of thebody upwardly and inwardly, as at I2 and spacing the end of the portionl2 away from the end of the adjacent part I I, so that it provides aninclined strut arm .jof considerable length to engage a different turnof the thread.

In the preferred arrangement,

the portion I2 is apertured to engage a bolt fastener, especially wherethe fastener is used to hold heavy parts in connection with automobileassemblies, will strip the bolt threads whenever the bolt is tightenedto the desired degree.

An object of the present invention is to make a fastener which may beused satisfactorily for holding heavy parts together without strippingthe bolt thread. In this connection, the invention is directed toward aconstruction which may be economically made and readily attached inbolt-receiving position.

Referring now to the drawings, Fig. 1 is a top plan view of a fastenerembodying my invention; Fig. 2 is a section taken on the line 2-2 inFig. 1; Fig. 3 is a top plan view of a modified form of the invention;Fig. 4 is a section taken on the line 4-4 in Fig. 3; Figs. 5 and 6 aretop plan views of other modifications; Figs. 7 and 8 are sections takenon the correspondingly numbered lines on Figs. 5 and 6, respectively;Fig. 9 is a top plan view of a modification of the invention; Fig. 10 isa section taken on the line Ill-Ill in Fig. 9; Fig. 11 is a sectiontaken on the lines ll-ll in Fig. 10 and Fig. 12 is a vertical sectionthrough a fastener showing a modified arrangement of the thread-engagingportion of the fastener; Fig. 13 is a top plan view of I anothermodification of the invention; Fig. 14 is a section taken on the linel4l4 in Fig. 13; Fig. 15 is a top plan view of a fastener of a furthermodification of the invention and Fig. 16

I is a section taken on the line I6|6 in Fig. 15.

Ordinarily, a threadless spring fastener is adapted to engage only oneturn of the bolt thread. My invention engages more than one turn andaccomplishes such result without threading the fastener.

of sheet-metal having a body Ill which may be arched upwardly andwhichhas yieldable bolt.

tional engagement with the thread is obtained In Fig. l, for example,the fastener is illustrated as comprising a strip thread and is disposedabove that portion H which comprises the point of entrance of the threadinto the fastener.

I have found that the shearing of the thread occurs at the point ofentrance, and that the utilization of the second thread-engaging partdirectly above the point of entrance by an upwardly inclined armmaterially longer than that at the entrance provides sufficient strengthto thefastener that the head of the bolt can be twisted off before thethread will be stripped. This arrangement is of major importance inproduction work, particularly in automotive assembly work.

The modification of Fig. 3 has the same parts and are designated in thesame manner as those -of Fig. 2, the difference being that the tongue I2is struck upwardly from a part of the body, whereas in Fig. l, thetongue [2 is formed'by bending the strip upwardly without any punchingoperation. The fastener of Fig. 4 is advantageous in those installationswhere a larger bearing surface against the part to be joined is desired.

In Figs. 5 and '7, the modification illustrated has one end of the bodyportion reversely bent to provide a lower arm 4| which has aboltreceiving aperture l5 therein. The arm may be spaced from the mainportion of the body sufficlently far to admit one of the parts Hi to bejoined, but the thread-engaging part of the fastener is the same as thatillustrated in Figs. 1 and 2 and so the parts are correspondinglynumbered.

The modification of Figs. 6 and 8 is similar to that'illustrated inFigs. 1 and 2, except for the fact that each .end of the body is bentupwardly and inwardly so as to provide two parts 12 instead of one part.

While I have shown the part I2 in some forms of the invention as beingmade by bending the end of the body upwardly, I may, if desired, form itby bending up the side of the body. In such case, however, there wouldbe more waste in the manufacture than would be the case where the end isbent upwardly. I prefer, therefore, to use that form which isillustrated.

The modification of Fig. 9 embodies a strip of metal wherein the. bodyportion [5 has a cir- I! may be struck upwardly out of the plane of thebody portion so as to make the marginal a relative movement between thearms ll and I2 with respect'to the body: thelongerarm moving 1 towardthe axis oi'thebolt at a faster rate than the shorter arm. Inasmuch asthe bolt arms are edges of the opening it conform to-the: helix of thebolt thread. One end of the body portion is bent upwardly and inwardlyto provide an arm 20, which has a recessed portion 2| that is adapted toengage a turn ofthe bolt thread,

which is above that engaged by the tongues. l8

and iii. In Fig. 10 the tongue I8 is shown-in solid lines as being inthe plane of thebody' portion, whereas the tongue I! is shown in broken.

lines as being raised above the plane of the body portion. rangement ismodified in that the tongue I8 is struck downwardly from the plane ofthe bodyf arm 25 may have a bolt-receiving aperture 26,

which is adapted to engage thesh'ank of the bolt and to coact with thebent portion 25 for preventing rotation or dislodgment of the fastenerwhen a bolt is threaded therethrough.

In Fig. I have shown a further modification, wherein the construction issimilar to that shown in Fig. 9, except for the fact that the corners ofthe arm are bent downwardly to provide prongs 80, which are adapted toengagethe body of the fastener, and thereby to limit the move-; ment ofthe arm 20 toward the body portion.

.This form of fastener has been developed as a result of a carefulanalysis as to the cause of the thread stripping, and after repeatedexperiments to overcome the difflculty. Engagement with the thread at aplurality of points by means of yieldable parts that are formed out ofthe body, by bending either the body, or a portion of it upwardly andinwardly upon itself, has distributed the stresses uniformly between thethread and the fastener, and has avoided the localization of stresses atthe point of entry.

Scientific investigation indicates that the remarkable holding powerprovided by this nut, heretofore referred to, is due to the fact thatthe bent over end portion of the fastener provides an inclined strut,extending from a region distant from the root of that intermediateportion of the body, which, by reason of the slitting and warping,provides in effect a short arm. The engaging edge of the long. strutwould swing through a sufficient arc, if the device were fiattened tomaterially bend the bolt.- However, the rigidity of the bolt itselfprevents such a bending and, accordingly, the fastener obtains aremarkably tight hold on the bolt.

The thread-engaging portion of the body shown at H or IE in the drawingsconstitutes in effect anarm which has its outer end or line of flexureapproximately only half as far from the bolt asthe outer end or line offlexure of the bent-over end portion I2 or 20. Consequently, as the armsare pulled downwardly toward the body consequent upon rotation of thebolt during the tightening operation, there is a In Fig. 12, however,thetongue ar-' attached tothe body, and have diflerent leverage, itfollows that the longerarm tends to move'at a faster rate than theshorter arm toward the axis of the bolt. It is that relative movementbetween.

the arms with respect to the bolt that results-in greatly-superiorholding power over a fastener having only the singlethreadengagingportion, as

a result of which a greatly improved resistance to loosening of the boltis obtained. In fact, the

holding power is so pronounced that upon tightening, the bolt will besheared before the threads will be stripped.

I claim:

l. A sheet metal fastening device, comprising a conical protuberancehaving an opening in the top thereof, the edge of the wall of whichprovides a thread for enga ement with a threaded element, an integralprojection overhanging said protuberance and provided with a notch toengage in the groove ofthe threaded element for the fastening devicebeyond the groove that receives said edge, and means formed asanintegral part of said projection to act as a stop to limit theflattening of said protuberance.

2. A sheet metal structure for receiving a threaded element, comprisinga member having a self-locking thread, integral means overhanging thethread and provided with a notch to engage in the groove of the threadedelement beyond that receiving the self-locking thread in the member, andstops formed on said means at the sides of said notch for engaging thesurface of said member adjacent thcself-locking thread whereby the sheetmetal structure is strengthened to withstand increased tightening.forces.

3. A sheet metal nut comprising a body providing a thread for engagementwith a threaded element, means overhanging said body and having a notchtherein for engaging-in the groove of the threaded element for said nutbeyond that engaged by said thread, and means formed as an integral partof said first-mentioned means extending toward said body to limit themovement of said means toward said body.

4. A sheet metal nut, comprising a strip of m'etal consisting of a bodyand a part projecting out of the plane of said body and having aselflocking thread therein, means to engage a thread of a threadedelement beyond the thread engaged by the Self-locking thread, and stopmeans formed on said means for engaging the upper surface of said partadjacent the self-locking thread Whereby said nut permits theapplication of increased tightening forces.

5. A sheetmetal nut having a portion providing a thread for engagementwith a threaded element and an integral projection overhangingsaidportion having a notch to engage the threaded element for the nut beyondthe thread in said portion, an integral body portion on said nut forattaching the nut to a structure enga ed thereby, and means integralwith said projection engaging said portion adjacent the threaded openingtherein for reinforcing the nut whereby increased tightening forces maybe app ied to said threaded element.

. 6. A sheet metal nut, comprising a body having a protuberance thereinprovided with an opening, the edge of saidopening being shaped toprovide a threadior a bolt. a portion formed integrally with 'said bodyand return-bent to overhang said protuberance. an opening portionaligned with said flrst-namdl opening.

' and lug means depending from said portion toward said bocly. 7. Asheet metal nut comprising ,a body with an opening for the passage of a.threaded bolt,

' the body being warped about the opening to provide a thread, and aleaf formed by bending the body over at an acute angle to itself, sothat two thread engaging arms are provided springing from differentregions and of different length so that the ends of the arms move indifferent arcs as the bolt is tightened.

8. A spring fastening device having a sheet material body, a bolt-threadengaging portion on the body shaped to conform with the helixof thethread of a bolt with which it is intended to be used, the threadengaging portion being formed with the body and extending forwardlytherefrom, the point to which it extends upwardly from the body beinglocated between the opening and one end of the body, the body haw ingone end thereof turned upwardly and inwardly in aninclined directiontoward the center thereof and terminating adjacent the opening andhaving a notch for receiving the bolt thread, the notch portion beingshaped to conform to the axis of the bolt thread, said fasteneroperating when the bolt is tightened to effect a movement of the upperthread engaging portion toward the axis of the bolt at a faster ratethan the lower bolt-engaging portion, whereby pressure is exertedagainst the thread in different degrees between the upper and lowerthread engaging portions.

9. A nut comprising a strip of flexible resilient sheet materialconsisting of a body having an opening through it, a portion of the bodyadjacent the opening being slitted and warped to produce a helicalthread at the end for engagement with a thread on a bolt. and an armabove said slitted and warped portion, said arm being provided by a bentportion of the strip on a line of fold transversely of the length of thestrip, said arm extending at an acute angle to the plane defining thebottom of the strip beneath it and formed at its endto engage anotherthread of the bolt.

10. A sheet metal nut comprising a strip of flexible resilient sheetmetalconsisting of a body having an opening through it, a portion of thebody adjacent the opening being slitted and warped to produce a helicalthread at the end for engagement with a thread on a bolt, and an armabove said slitted and warped portion, said armbeing provided by abent-over portion of the strip on a line of 'fold transverse of thestrip, said arm extending at an acute angle to the plane defining thebottom of the strip beneath it, the

free end of said arm being warped and having a concavity adapted toengage another thread of the bolt, the bolt-engaging portions of the twoarms being spaced apart by the pitch distance of the bolt or a multiplethereof, and said arm being sumciently longer from its point of flexurethan said warped portion to bring the engaging portions. into coactiondifferent regions the same-helical th silient sheet material,

- and formed at its end of a bolt. a

ii. A nut comprising-.;a

ting'otabody having opening immune-wrest): the body adjacent the opening,beinglongitudinally slitted along two lines toproduce' a short arm, thematerial thereof being warped jtoi give a helical thread at the end forenga ement with athread on'a bolt, anda longer arm provided by aboutportion of the strip one, line of fold transversely of thelengthof-the-strip and extending above said short am, said longerarmextending at an acute, angle to the body ofi'the strip beneath it v toengage. another thread ofthebo1t.-

12. A sheet metal nut'comprising astrip of spring metal consi'stin'g of'a body having an opening through it, a portion of the body adjacent theopening- 'being'sliton two lines to produce a shortarm which is'warpedto produce a helical thread at the end for engagement with a thread on abolt, and a longer arm provided by a bent-over portion of the strip on asubstantially abrupt line of fold transverse of the strip, a

said longer arm extending above the short arm at an acute angle. to thebody of the strip beneath it, the free end of the longer arm beingwarped and havinga concavity adapted to engage another thread of thebolt, the bolt-engaging portions of the two arms being spaced apart bythe pitch distance of the bolt or a multiple thereof, and the longer armbeing sufflciently longer than the short arm to bring their engagingportions into coaction with different regions of the same helicalsurface on the bolt.

13. A spring fastening device for use on a threaded bolt comprising abody having an opening adapted to surround the bolt and having twoportions adapted to engage different threads of the bolt, one engagingportion being the .warped wall about an opening through the intermediateportion, of the fastening device, the other engaging portion being awarped recess in the end of an arm formed by bending backwardly theextreme portion of the strip, such backwardly bent portion leaving thebody of the strip comparatively abruptly at an acute angle and extendingfrom the region of bend in an inclined direction a materially greaterdistance to the region where it may engage the bolt shank than extendsthe intermediate body portion from the root of the warped arm to theregion where it may engage the bolt shank.

14. A fastener of flexible resilient sheet material comprising a baseportion from which are deformed thread-engaging portions, the body ofsaid fastener having a portion bent over one of said thread-engagingportions at an acute angle to the base plane of the fastener and formedso as to provide an additional thread-engaging poring portion which itoverlies but substantially double its length.

GEORGE a. TINNERMA'N.

of fl

